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Causal Agent:
Watermelon Mosaic Virus-2 (WMV-2) Papaya Ringspot Virus - Type W (PRSV-W),
formerly known as Watermelon Mosaic Virus - 1. Infects only
cucurbits.
Distribution:
Worldwide, though PRSV-W is more common in tropical regions while WMV-2
is often found in temperate areas.
Symptoms:
Both viruses infect all cucurbits. WMV-2 also infects legumes and some
weeds. Infected leaves first develop a yellowing between the veins.
Later, the leaf becomes misshapen and the leaf tissue around the major
veins may develop a tendril-like appearance. New leaves are mottled,
blistered and distorted. Infected plants are stunted. Fruit can become
bumpy and severely distorted with occasional changes in color.
Conditions
for Disease Development:
The virus is present in cucurbits, some perennial weeds and legumes.
Aphids and in some cases leafminers can transmit the virus from infected
to healthy plants. Once in the field, the virus can be spread by farm
machinery and pickers, as well as by insects. The disease seems to be most
severe during the warm growing seasons.
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